Golf Clubs With Golf Club Heads Having Grooves

ABSTRACT

A golf club with a golf club head having a plurality of grooves formed in a ball striking surface of the golf club head wherein the side walls of each groove slope inwardly from the striking face toward a bottom of the groove at an angle of 25.5 to 27.5 degrees from an axis of symmetry extending perpendicular from the striking face.

FIELD

This invention relates generally to golf clubs. In particular, the invention relates to golf clubs having grooves formed in a front face of a golf club head.

BACKGROUND

The popularity of the game of golf has increased immensely in recent decades. All manner of players are looking for equipment that will improve an individual's performance, thereby making the game more enjoyable. Golf's regulating bodies, such as the United States Golf Association (“USGA”), institute rules and limitations on the design, configuration, etc. of golf clubs, and thus clubs must be designed to remain within the regulations of the ruling body, while still providing expected or improved performance.

One such regulation deals with club head grooves and their shape, size, spacing, configuration, etc. The USGA has enacted regulations limiting the size, shape, and volume of golf club grooves, including for the groove limitations for clubs having a loft angle greater than 25°. Limiting groove sizes and edge angles is expected to limit the club's ability to channel away water, grass, and other debris during a ball strike and is expected to limit or reduce the spin induced on the ball by the ball strike. These features are expected to result in more inconsistent shots (particularly out of the rough). Accordingly, there is a need in the art for golf club heads having conforming grooves that have improved or more consistent performance.

SUMMARY

The following presents a general summary of aspects of the invention in order to provide a basic understanding of the invention and various features of it. This summary is not intended to limit the scope of the invention in any way, but it simply provides a general overview and context for the more detailed description that follows.

Aspects of this invention relate to golf clubs and golf club heads having grooves formed in a ball striking surface of the front face of the golf club head wherein the grooves are formed with a wall angle of approximately 27 degrees from a reference axis extending perpendicular to the front face of the golf club head such that the distance between the sidewalls decrease from the top of the groove to the bottom of the groove. The reference axis may be considered an axis of symmetry centered in the groove.

The groove configurations of the present invention provide optimized collective dimensions allowing the grooves to better grip a golf ball upon impact and as a result, provide highly consistent spin properties and trajectory properties for all playing conditions, wherein, in at least some of the examples of this invention, the groove configurations are in conformance with the Rules of Golf as currently promulgated by the USGA.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention and certain advantages thereof may be acquired by referring to the following detailed description in consideration with the accompanying drawings, in which:

FIG. 1 is an example golf club having a plurality of grooves formed in a ball striking surface of a front face of the club head in accordance with aspects of the invention.

FIG. 2 is a front view of an example golf club head having a plurality of grooves (shown enlarged) with at least some illustrative aspects of the invention.

FIG. 3 is a cross-sectional view of example groove configurations used as an illustrative aid to explain various terms as used in this specification.

FIG. 4A is a front view of an example groove in accordance with at least some illustrative aspects of the invention.

FIG. 4B is a schematic perspective view of the groove of FIG. 4A in accordance with at least some illustrative aspects of the invention.

FIG. 4C is a cross sectional view of the groove of FIG. 4A taken along line 4C-4C of

FIG. 4A extending from a toe of the golf club head to a heel in accordance with at least some illustrative aspects of the invention.

FIGS. 5A and 5B illustrate front views of alternate groove configurations in accordance with at least some aspects of the invention.

FIG. 6A is a cross sectional view of example grooves having a sidewall of the groove in accordance with at least some aspects of the invention.

FIG. 6B is a cross sectional view of example grooves having a sidewall of the groove in accordance with at least some other aspects of the invention.

FIGS. 7A and 7B depict impact areas for comparative and inventive golf club heads.

The reader is advised that the attached drawings are not necessarily drawn to scale.

DETAILED DESCRIPTION

In the following description of various example structures in accordance with the invention, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various example articles, including one or more golf club or golf club head structures. Additionally, it is to be understood that other specific arrangements of parts and structures may be utilized and structural and functional modifications may be made without departing from the scope of the present invention. Also, while the terms “top,” “bottom,” “front,” “back,” “rear,” “side,” “underside,” “overhead,” and the like may be used in this specification to describe various example features and elements of the invention, these terms are used herein as a matter of convenience, e.g., based on the example orientations shown in the figures and/or the orientations in typical use. Nothing in this specification should be construed as requiring a specific three dimensional or spatial orientation of structures relative to external structures in order to fall within the scope of this invention. Further, the invention generally will be described as it relates to wedge-type golf clubs. However, aspects of the invention may be used with any of several types of golf clubs, including iron-type clubs, wood-type golf clubs, hybrid type golf clubs, and the like, and nothing in the specification or figures should be construed to limit the invention to use with the wedge-type golf clubs described.

A. General Description of Illustrative Golf Clubs with Golf Club Heads Having Grooves

In general, as described above, aspects of this invention relate to golf clubs or golf club head structures. More detailed descriptions of aspects of this invention follow.

1. Example Golf Clubs and Golf Club Heads Having Grooves

Aspects of this invention relate to golf club and golf club head structures. In at least some examples, the golf club head may include a golf club head body having a toe, a heel, a top or crown, a sole, a rear and a front face, the front face including a ball striking surface. The golf club head may further include a plurality of grooves formed in the ball striking surface. In some arrangements, at least one groove of the plurality of grooves has a first sidewall and a second sidewall, each sidewall extending inward from the front ball striking face of the golf club head body to a bottom or interior end of the groove, wherein each side wall slopes inwardly toward the bottom of the groove at an angle of approximately 27 degrees from a reference axis perpendicular to the face of the club such that the distance between the sidewalls decreases from the top of the groove to the bottom of the groove.

Other example golf club head structures in accordance with this invention may include a plurality of grooves formed in the ball striking surface, wherein at least a first groove of the plurality of grooves has a first end arranged proximate the toe and a second end arranged proximate the heel, wherein the first groove has a first sidewall and a second sidewall, each sidewall extending inward from the front ball striking face of the golf club head body to a bottom or interior end of the groove, wherein each side wall slopes inwardly toward the bottom of the groove at an angle of approximately 27 degrees from a reference axis perpendicular to the face of the club such that the distance between the sidewalls decreases from the top of the groove to the bottom of the groove.

Still other aspects of this invention relate to golf clubs including a golf club shaft and a golf club head connected to one end of the shaft, wherein the golf club head is any of the various types described above. While aspects of this invention may be practiced on any type of golf club head (e.g., drivers, fairway woods, hybrids, and putters), in some examples, aspects of this invention will be practiced with wedge type and iron type golf clubs and golf club heads. Also, aspects of this invention may be practiced on clubs generally known as or corresponding to 5-irons to 9-irons, pitching wedges, sand wedges, gap wedges, lob wedges, and the like.

As some more specific examples, golf clubs and golf club heads in accordance with at least some examples of this invention will have a loft angle of 25° or more, and in some examples, within a range of 25° to 68°, or even within a range of 25° to 64°. Some more specific examples of this invention will include golf clubs and golf club heads having loft angles within the range of range of 45° to 64°.

The groove design of the present invention allows for improved ball spin in “mist” conditions creating similar ball spin as in a dry condition (e.g. the ball loses less spin in mist conditions as compared with other groove structures.)

2. Example Methods of Forming Golf Clubs and Golf Club Heads

In at least some aspects, methods of forming golf clubs and/or golf club heads may include forming a golf club head body including a toe, a heel, a top or crown, a sole, a rear and a front face, the front face including a ball striking surface (e.g. by a casting, forging, molding, or other process.) The methods further include forming a plurality of grooves in the ball striking surface of the golf club head body. In certain embodiments, the grooves may be formed in a stamping operation or in a cutting or grinding operation. Other suitable manufacturing operations can also be used including a metal injection molding process. The methods may further include connecting the golf club head to a shaft.

Additional aspects and specific examples of the articles described above will be described in detail more fully below. The reader should understand that these specific examples are set forth merely to illustrate examples of the invention, and they should not be construed as limiting the invention.

B. Detailed Description of Example Golf Clubs, Golf Club Heads and Methods of Forming Golf Clubs and Golf Club Heads According to the Invention 1. Golf Club Heads Containing Grooves

Referring to the figures and following discussion, example golf clubs and golf club heads in accordance with the present invention are described. As discussed above, the golf club and club head structures described herein may be described in terms of iron-type golf club, including wedge-type clubs. However, the present invention is not limited to the precise arrangements disclosed herein but applies to golf clubs generally, including wood-type clubs, hybrid clubs, and the like.

Golf club heads may generally include a plurality of different regions, segments, portions, ends, etc. In an example embodiment, a golf club head may generally include a front ball striking face, a rear, a toe, a heel, a top or crown and a sole. The golf club heads may include a single or a multiple piece construction and structure, e.g., including one or more individual parts corresponding to a sole, a front face (optionally including a ball striking surface that may be integrally formed therein or attached thereto), a top or crown, a bottom or sole, a rear, etc. If desired, various portions of the club head structure may be integrally formed with one another, as a unitary, one piece construction, without departing from the invention (e.g., the front face and/or rear may be integrally formed with the sole and/or top, etc.). Optionally, if desired, the various portions of the club head structure (such as the sole, the top, the face member, the rear, etc.) individually may be formed from multiple pieces of material without departing from this invention (e.g., a multi-piece top, a multi-piece sole, etc.). Also, as other alternatives, if desired, the entire club head may be made as a single, one piece, unitary construction, or a front face may be attached to a one piece club head rear (optionally, a hollow body, etc.). More specific examples and features of golf club heads and golf club structures according to this invention will be described in detail below in conjunction with the example golf club structures illustrated in the Figures.

FIG. 1 generally illustrates an example golf club 100 and/or golf club head 102 in accordance with this invention. In addition to the golf club head 102, the overall golf club structure 100 of this example includes a hosel 104, a shaft 106 received in and/or inserted into and/or through the hosel 104, and a grip or handle 108 attached to the shaft 106. Optionally, if desired, the external hosel 104 may be eliminated and the shaft 106 may be directly inserted into and/or otherwise attached to the head 102 (e.g., through an opening provided in the top of the club head 102, through an internal hosel (e.g., provided within an interior chamber defined by the club head 102), etc.).

The shaft 106 may be received in, engaged with, and/or attached to the club head 102 in any suitable or desired manner, including in conventional manners known and used in the art, without departing from the invention. As more specific examples, the shaft 106 may be engaged with the club head 102 via a hosel 104 and/or directly to the club head structure 102, e.g., via adhesives, cements, welding, soldering, mechanical connectors (such as threads, retaining elements, or the like), etc.; through a shaft-receiving sleeve or element extending into the club head body 102; etc. The shaft 106 also may be made from any suitable or desired materials, including conventional materials known and used in the art, such as graphite based materials, composite or other non-metal materials, steel materials (including stainless steel), aluminum materials, other metal alloy materials, polymeric materials, combinations of various materials, and the like. Also, the grip or handle 108 may be attached to, engaged with, and/or extend from the shaft 106 in any suitable or desired manner, including in conventional manners known and used in the art, e.g., using adhesives or cements; via welding, soldering, or the like; via mechanical connectors (such as threads, retaining elements, etc.); etc. As another example, if desired, the grip or handle 108 may be integrally formed as a unitary, one-piece construction with the shaft 106. Additionally, any desired grip or handle 108 materials may be used without departing from this invention, including, for example: rubber materials, leather materials, rubber or other materials including cord or other fabric material embedded therein, polymeric materials, and the like.

The club head 102 itself also may be constructed in any suitable or desired manner and/or from any suitable or desired materials without departing from this invention, including from conventional materials and/or in conventional manners known and used in the art. For example, in the example club head 102 shown in FIG. 1, the club head 102 includes a front face 101 that generally includes a ball striking surface (optionally including a ball striking face plate integrally formed with the ball striking surface or attached to the club head such that the face plate and a frame together constitute the overall ball striking surface.) The club head 102 may further include a top surface 103, a sole 105, a toe 107 and a heel 109. The club head 102 may also include a rear (not shown in FIG. 1).

A wide variety of overall club head constructions are possible without departing from this invention. For example, if desired, some or all of the various individual parts of the club head 102 described above may be made from multiple pieces that are connected together (e.g., by welding, soldering, or other fusing techniques; by mechanical connectors; by adhesives or cements etc.). The various parts (e.g., crown, sole, front face, rear, etc.) may be made from any desired materials and combinations of different materials, including materials that are conventionally known and used in the art, such as metal materials, including lightweight metal materials, and the like. More specific examples of suitable lightweight metal materials include steel, titanium and titanium alloys, aluminum and aluminum alloys, magnesium and magnesium alloys, nickel and nickel alloys, etc. Additionally or alternatively, the various parts of the club head may be formed of one or more composite materials. The club head 102 also may be made by forging, casting, or other desired processes, including club head forming processes as are conventionally known and used in the art.

The various individual parts that make up a club head structure 102, if made from multiple pieces, may be engaged with one another and/or held together in any suitable or desired manner, including in conventional manners known and used in the art. For example, the various parts of the club head structure 102, such as the front face 101, ball striking surface 102 a, the top 103, the sole 105, etc., may be joined and/or fixed together (directly or indirectly through intermediate members) by adhesives, cements, welding, soldering, or other bonding or finishing techniques; by mechanical connectors (such as threads, screws, nuts, bolts, or other connectors); and the like. If desired, the mating edges of various parts of the club head structure 102 may include one or more raised ribs, tabs, ledges, or other engagement elements that fit into or onto corresponding grooves, slots, surfaces, ledges, openings, or other structures provided in or on the facing side edge to which it is joined. Cements, adhesives, mechanical connectors, finishing material, or the like may be used in combination with the raised rib/groove/ledge/edge or other connecting structures described above to further help secure the various parts of the club head structure 102 together.

The dimensions and/or other characteristics of a golf club head structure according to examples of this invention may vary significantly without departing from the invention, and the dimensions may be consistent with those commonly used in the art for similar club heads and clubs.

The golf club head 102 of FIG. 1 further includes a plurality of grooves 120 formed in its front face 101. These grooves 120 extend across the front face 101 in a substantially horizontal arrangement in the toe 107 to heel 109 direction of the golf club head (with the club head soled and/or oriented in a ball address position.)

FIG. 2 illustrates a golf club head 202 illustrating enlarged substantially horizontal grooves 220. The grooves 220 are generally straight and parallel and have a symmetrical cross-section. The width, spacing, and cross-section of the grooves 220 may be consistent throughout the impact area. The grooves 220 shown in FIG. 2 may be formed in the club head 202 after manufacture of the club head 202 or front face 201 using various techniques, such as but not limited to machining, stamping, grinding, and cutting in certain example embodiments.

As shown in FIG. 2, the grooves 220 may be formed such that the open top portion is substantially rectangular (e.g., the sidewalls 222 may meet the end walls 224 at the toe and heel areas of each groove 220 at a substantially 90° angle along the front face 201 of the golf club head 102). Alternatively, the edges may have other shapes without departing from this invention, including tapered or sloped edges that more gradually transition from one sidewall 222 to the other.

Golf club heads may be manufactured to have dimensions consistent with Appendix II of The Rules of Golf (2010-2011) as promulgated by the USGA (“the Rules”) hereby incorporated by reference in its entirety. Grooves are within the purview of the Rules and club heads of the present invention must include grooves that fall within the parameters of the groove rules in order to produce a club head that complies with USGA Rules. For example, for clubs other than driving clubs, the cross-sectional area (A) of a groove divided by the groove pitch (W+S) must not exceed 0.0030 square inches per inch (0.0762 mm²/mm).

A/(W+S)≦0.0030 in²/in.

W is the width of each groove and S is the distance between edges of adjacent grooves. Golf club heads in accordance with at least some examples of the present invention will conform to this Rule and yet provide an unexpected superior performance.

FIG. 3 is a cross sectional view of some example grooves used as an illustrative aid to explain various terms and definitions as used in this specification (and as used in the Rules). FIG. 3 shows two adjacent grooves 250 on the ball striking surface 240 of an iron type golf club head (the view of FIG. 3 is looking down the longitudinal length of a groove (e.g., toward the club head toe or the club head heel). Each groove 250 of this example includes a first entry radius 252 (transitioning from the ball striking surface 240 to the groove 250 interior), a first side wall 254, a bottom wall 256, a second side wall 258 (opposite the first side wall), and a second entry radius 260 (transitioning from the ball striking surface 240 to the groove 250 interior). Consistent with Appendix II of the Rules (2010-2011) as promulgated by the USGA and as shown in FIG. 3, the groove 250 edge is defined by a tangent point T of the groove surface G and a plane P oriented at an angle of 30° with respect to horizontal, when the club head 200 is oriented to have the ball striking surface 240 horizontal. See 2012-2015 Supplement to the Rules http://www.usga.org/Rule-Books/Rules-on-Clubs-and-Balls/Supplement-C/ Section (I) Rounding which specifies the edge radius rule.

The grooves 250 have a cross-section with a bottom portion or surface 256 being narrower than the groove width W at the top or open side. The groove width W at the top is defined as the distance between the tangent points T of a single groove 250. For instance, the grooves 250 may have a generally trapezoidal cross-section with a top portion being open such that sidewalls 254 and 258 of the grooves 250 may taper toward each other as they extend from the front face 240 of the golf club head inward, toward a rear of the golf club head. That is, a bottom portion of opposing sidewalls 254, 258 may be closer together than a top portion of the sidewalls 254, 258. The grooves 250 also may be separated from one another by a distance “S” as shown in FIG. 3 (i.e., the distance from the tangent point T of one groove and the closest tangent point T of the adjacent grove 250.) As further shown in FIG. 3, the groove 250 may define an angle A1 generally taken from one of the tapered sidewalls 254, 258 and an axis of symmetry AS positioned generally as a center point of the groove 250. The axis of symmetry AS in this illustration is a vertical reference line that is perpendicular to the ball striking face of the golf club. It is understood that a combined angle between the angled sidewalls 254, 258 is twice the angle A1. A pitch distance PI may be defined between respective centerlines between adjacent grooves.

As some additional examples, as shown by FIG. 3, the cross-sectional area A defined by the groove 250 (i.e., the area between the groove surface G and the extension E of the ball striking face 240 over the groove 250) may be controlled such that the following relationship is satisfied in accordance with the Rules: A/(W+S)≦0.0030 in²/in. It is understood that the groove structure of the present invention includes area defined in part by the first entry radius 252 and the second entry radius 260.

FIGS. 4A-4C conceptually illustrate one example groove arrangement that may be used in accordance with this invention. FIG. 4A is a front view of the groove 420. The groove 420 is shown in isolation and only a portion of the front face 401 of the golf club head is shown in FIGS. 4A and 4C in order to more clearly illustrate the features of the groove 420. The groove 420 includes sidewalls 422 and end walls 424. The groove 420 also includes a bottom 426. As shown schematically in FIG. 4B, the sidewalls 422 taper as they extend from the front face toward the bottom of the groove 420 such that the bottom portions of the sidewalls 422 are closer together than the top portions.

In this illustrated example, the groove 420 has a generally rectangular appearance or outer perimeter from the front, as shown in FIG. 4A. That is, the end walls 424 and sidewalls 422 meet at substantially 90° angles. Further, the end walls 424 meet the bottom 426 at substantially 90° angles. FIG. 4C is a cross-sectional view of the groove 420 taken along line 4C-4C in FIG. 4A as it extends longitudinally from the toe side of the club head toward the heel side, and this figure illustrates the end walls 424 meeting the bottom 426 of the groove 420 at a substantially right angle.

FIGS. 5A and 5B illustrate front views of additional example groove shapes. Groove 520 in FIG. 5A includes end portions that converge to a point. This convergence to a point may extend downward to the bottom of the groove 520 (e.g., the end walls 524 may be substantially perpendicular to the bottom surface 526). Alternatively, if desired, more tapered or sloped end wall surfaces 524 may be provided. FIG. 5B illustrates a front view of a groove 540 having a substantially oval shape (which may include tapered or perpendicular side and/or end walls). Although these are two possible groove configurations, many more groove configurations are available and possible without departing from this invention.

The clubs according to the invention may have surface roughness between the grooves, e.g., applied by laser, sand blasting, water jet blasting, milling, grinding, etc. This type of surface Roughness must comply with the Rules, Appendix II, 5b (ii).

FIG. 6A is illustrative of a cross-sectional view of example grooves in accordance with an aspect of the invention. FIG. 6A shows two adjacent grooves 650 on the ball front face or striking surface 601 of a wedge-type golf club head (similar to FIG. 3, the view of FIG. 6A is looking down the longitudinal length of a groove, e.g., toward the club head toe or the club head heel). Each groove 650 of this example includes a first side wall 654, a bottom wall 656, and a second side wall 658 (opposite the first side wall).

Similar to FIG. 3, the grooves 650 have generally V-shaped cross-sectional shapes with a flat or truncated bottom; in other words, the grooves 650 have a generally trapezoidal cross-section with a top portion being open. This provides grooves 650 with a bottom portion or surface 656 narrower than the groove width W at the top or open side. Stated differently, the sidewalls 654 and 658 of the grooves 650 taper toward each other as they extend from the front face 601 of the golf club head inward, toward a rear of the golf club head. That is, a bottom portion of opposing sidewalls 654 and 658 are closer together than a top portion of the sidewalls 654 and 658. In this aspect of the invention, the grooves are symmetrical in cross-section. It is understood that the grooves 650 may include entry radii (R′) as discussed above.

In the specific, non-limiting, example shown in FIG. 6A and FIG. 6B, the side wall angle is approximately 27 degrees from a reference line or axis of symmetry AS (a reference axis normal to the face plane shown in FIGS. 6A and 6B), the depth d of 0.016 inches (0.4 mm), the width W at the top of the groove is 0.028 inch (0.71 mm), and the distance S is 0.094 inch (2.39 mm). From such dimensions, the cross-sectional area A of the groove 650 is readily determined Such area A, when divided by the groove pitch (W+S) does not exceed 0.0030 square inches per inch.

In other aspects of the invention, dimensions disclosed herein may be provided with certain tolerances and ranges while still falling within the scope of the present invention. For example, each sidewall has a 25.5 to 28.5 degree angle from a reference line or axis of symmetry AS (a reference axis normal to the face plane shown in FIG. 6A.) Alternatively, the angle may also be measured from sidewall 654 to sidewall 658 and thus may be 51 to 57 degrees.

In accordance with at least some examples of this invention, the grooves 650 may have a depth “d” of 0.013 to 0.018 inches (0.33 to 0.46 mm) (and in some examples, from 0.015 to 0.017 inches (from 0.38 to 0.43 mm) and even from 0.015 to 0.016 inches (from 0.38 to 0.41 mm)) The depth is a depth taken from the top of the groove to the bottom of the groove.

In accordance with at least some examples of this invention, the grooves 650 may have a width “W” at the top of the groove is from 0.025 to 0.030 inches (from 0.64 to 0.76 mm) (and in some examples, from 0.027 to 0.028 inches (from 0.68 to 0.72 mm)). The width W2 at the bottom of the groove may be determined by the width W, the depth d, and the side wall angle.

In accordance with at least some examples of this invention, the grooves 650 may also be separated from one another (distance “S” in FIG. 3) by a distance of from 0.085 to 0.098 inches (2.16 to 2.49 mm), and in some examples, from 0.090 to 0.095 inch (2.28 to 2.41 mm) or even from 0.094 to 0.095 inch (2.38 to 2.41 mm.) Per the Rules, the distance S between edges of adjacent grooves must not be less than three times the width W of the grooves, and not less than 0.075 inches (1.905 mm).

In accordance with at least some examples of this invention, the groove area may be (A) is 0.00028 to 0.00036 in². In accordance with at least some examples of this invention, the area (A) of each of said grooves divided by groove pitch (S+W) is 0.0018 to 0.0030 in²/in or 0.0023 to 0.0030 in²/in.

As shown in FIG. 6B and appreciated from FIG. 3, the edges between the side walls and top surface of the face may be rounded with a lead in radius R as necessary in compliance with the Rules. In one particular embodiment, the lead in radius may be 0.0073 inches (0.19 mm.) One skilled in the art would know how to do the calculation.

Further, as exemplified in FIG. 1, grooves 120 may extend in a direction across the ball striking face of the club from the toe area toward the heel area and may be, for example, from 0.5 to 2.5 inches long (12.7 to 63.5 mm) and in some examples, from 0.75 to 2.25 (19.1 to 57.2 mm) or even from 1.8 to 2.2 inches (45.7 to 55.9 mm) in length. The length of the grooves may depend, at least in part, on the size and shape of the front face of the golf club head. Further, not all of the grooves may be of equal length as seen in FIGS. 1 and 2. The determination of the length of the grooves is within the skill of the art and based on the type of club head, size of club head, and the like.

The number of grooves on a wedge-type golf club head may depend, for instance, on loft angle. For example, a greater loft angle may provide a larger surface area; hence, more grooves may be desired. The determination of the number of the grooves is within the skill of the art and based on the type of club head, size of club head, and the like. With the groove structures described herein, an idealized number of grooves can be positioned within a set linear distance on the ball's striking face.

When a golf ball is struck by a golf club head, the side of the ball in contact with the face flattens as the ball cover and core compress. This flattening puts more area of the ball surface into contact with the club face (the ball/face contact area is represented in FIGS. 7A and 7B by the circular area). This area may vary, for example, depending on swing speeds, the layer (or other structural) features of the ball, etc. FIGS. 7A and 7B show that, despite the fact that the comparative groove contacts a larger number of grooves within the ball/face contact area than the inventive grooves (seven grooves within the circle of FIG. 7B v, six grooves within the circle of FIG. 7A), the area and volume of grooves within the circle is greater for FIG. 7A v. FIG. 7B. This is due to the selection of groove features, such as groove sidewall angle, groove width, groove depth, etc. Having a larger groove volume and/or area is advantageous, for example, to improve spin (by an increased area of grooves in contact with the ball surface) and/or to improve the groove's ability to wick away moisture and debris from the area if contact with the ball (due to the larger groove volume).

Thus FIG. 7A depicts the impact area by a golf ball on the impact side of a golf club head having grooves in accordance with the present invention. FIG. 7B depicts the impact area by a golf ball on the impact side of a golf club head having grooves in accordance with a comparative golf club head. As can be easily seen, a greater number (7) of grooves (which are closer together) appear under the impact area of the comparative groove whereas a smaller number (6) of grooves (which are further apart) appear under the impact area of the comparative groove. Notably, both groove configurations comply with the Rules. However the volume of the grooves under the impact area for the grooves according to this invention is about 12% higher than the Comparative Grooves, and the area of the grooves under the impact area for the grooves according to the invention is about 30% than the Comparative Grooves. Therefore the groove pattern according to the invention provide increased groove volume and groove contact area with the ball despite having fewer grooves in contact with the ball.

As discussed above, the present invention may be applicable to any suitable golf club head face. Aspects of the invention are particularly directed to a wedge-type golf club head. Wedge golf club heads having grooves in accordance with the present invention have performance consistent with other wedges having grooves but provides unexpected superior performance under mist or wet conditions, e.g. playing in morning dew, playing in wet conditions, etc.

2. Methods of Making the Grooves

The grooves may be made in the face of the golf club head by any suitable method such as machining, stamping, grinding, milling, cutting and the like. Such methods are within the skill of the art. One issue recognized with stamping is the stamped groove can create a swell. Hence, if a stamped groove is desired, a double stamping technique may be used to eliminate the swell.

3. Clauses

Notwithstanding the claims, the invention is also defined by way of the following clauses:

-   -   1. A golf club head comprising a substantially flat striking         face and a plurality of grooves formed therein,     -   wherein at least one of said grooves comprises:     -   side walls wherein each side wall slopes inwardly from the         striking face toward a bottom of the groove at an angle of 25.5         to 28.5 degrees from an axis of symmetry extending perpendicular         from the striking face;     -   a depth extending perpendicular from the striking face to the         bottom of the groove of 0.013 to 0.018 inch; and     -   wherein spacing between adjacent groove edges is 0.085 to 0.098         inches.     -   2. A golf club head comprising a substantially flat striking         face and a plurality of grooves formed therein,     -   wherein at least one of said grooves comprises:     -   side walls wherein each side wall slopes inwardly from the         striking face toward a bottom of the groove at an angle of 25.5         to 28.5 from an axis of symmetry extending perpendicular from         the striking face;     -   a depth extending perpendicular from the striking face to the         bottom of the groove of 0.013 to 0.018 inch; and     -   a width at the top of the groove of 0.025 to 0.030 inches.     -   3. A golf club head comprising a substantially flat striking         face and a plurality of grooves formed therein,     -   wherein at least one of said grooves comprises:     -   side walls wherein each side wall slopes inwardly from the         striking face toward a bottom of the groove at an angle of 25.5         to 28.5 from an axis of symmetry extending perpendicular from         the striking face; and     -   a width at the top of the groove of 0.025 to 0.030 inches;     -   wherein spacing between adjacent grooves is 0.085 to 0.098         inches.     -   4. The golf club head according to any of the preceding clauses         wherein the angle is 26.5 to 27.5.     -   5. The golf club head to any of the preceding claims wherein the         depth is 0.015 inches to 0.017 inches.     -   6. The golf club head to any of the preceding claims wherein the         spacing is 0.090 to 0.095 inches.     -   7. The golf club head to any of the preceding claims wherein the         area of each of said grooves divided by groove pitch is 0.0018         to 0.0030 in²/in.     -   6. The golf club head to any of the preceding claims wherein the         area of each of said grooves divided by groove pitch is 0.0023         to 0.0030 in²/in.     -   7. The golf club head to any of the preceding claims wherein a         groove area (A) is 0.00028 to 0.00036 in².     -   8. The golf club head to any of the preceding claims wherein the         grooves comply with the USGA Rules of Golf dated 2011-2012.     -   9. A golf club head comprising a substantially flat striking         face and a plurality of grooves formed therein,     -   wherein at least one of said grooves comprises:     -   side walls wherein each side wall slopes inwardly from the         striking face toward a bottom of the groove at an angle of 25.5         to 28.5 degrees from an axis of symmetry extending perpendicular         from the striking face;     -   a depth extending perpendicular from the striking face to the         bottom of the groove of 0.013 to 0.018 inch;

a groove width extending across the top of the groove of 0.025 to 0.030 inch;

-   -   a groove area is 0.00028 to 0.00036 in²;     -   wherein the area of each of said grooves divided by groove pitch         is 0.0018 to 0.0030 in²/in;

wherein spacing (S) between adjacent grooves is 0.085 to 0.095 inches; and

-   -   the loft angle of the club head is 44° to 70°.

4. Examples and Comparisons Example 1

Five different iron-type club heads with different groove structures were tested under mist and dry conditions. The clubs had the following characteristics:

Compar- Inven- Inven- Compar- Compar- ative tive tive ative ative Sample #1 Sample #1 Sample #2 Sample #2 Sample #3 Groove Stamped Stamped Cut Cut Cut Structure Groove 24 27 27 Angle Groove 0.022 0.028 0.027 0.027 0.029 Width (avg) Groove 0.013 0.018 0.018 0.014 0.016 Depth (avg) Groove 0.00018 0.00031 0.00033 0.00030 0.00040 Area (avg) Separation 0.080 0.087 0.088 0.094 0.113 (avg) Area/Pitch 0.0018 0.0027 0.0029 0.0025 0.0028 (avg) Loft Angle 60 60 60 59.75 60 (degrees) Robot 35 9/16 35¼ 35¼ 35 5/16 35 7/16 Length (inches) Total Weight 479.8 484.5 485.5 476.1 476.8

In a first test, club head performance was compared with respect to spin rates measured from hits using a robot such that the hits had a consistent speed, head path, and angle for a target distance (ball flight distance) of about 30 yards. Such tests were performed under dry and mist conditions.

Mist tests were conducted with a Fluidotech piston pump; 10-20 gpm, water reservoir (1-2 gallons); 30° mist nozzle; and 6-10 feet nylon tubing. The following protocol was followed: 1) Setup the swing robot for club and launch parameters. 2) Prime pump and test mist pattern. 3) Position mist nozzle above ball so the mist cone wets the back of the ball and covers the club head path 4 to 6 inches prior to ball impact; adjust mist nozzle if needed. 4) Wet club face with water using damp towel or nylon brush prior to first hit. 5) Place ball on robot tee, start mist pump and hit one shot to evenly wet and distribute water on club face. Allow club to return through impact area and turn off pump. Discard the shot. 6) Start the shot series within 30 seconds; place ball on tee, start mist pump, and hit shots. Continue to run the mist pump through the test sequence. 7) Repeat steps 4 and 5 when time between sequential shots and/or test setup exceeds 30 seconds.

The table below provides comparisons of the results including % spin lost or gained in mist conditions over dry conditions.

Dry Mist Club (rpm) (rpm) % Diff Comparison Sample #1 6113 3060 −49.9 Inventive Sample #1 5959 4058 −31.9 Inventive Sample #2 6160 4623 −24.9 Comparison Sample #2 5884 3482 −40.8 Comparison Sample #3 6141 3254 −47.0

Inventive Sample #2 performed the best followed by Inventive Sample #1. Notably, the wet conditions did not result in as much spin loss for the wedges in accordance with this invention as compared to the comparative wedges. Thus, the wedges according to these examples of the invention performed more consistently under the wet and dry conditions.

In a second test, spin rates were measured from hits using a robot such that the hits had a consistent speed, head path, and angle for a target distance of about 60 yards. The table below provides comparisons of the results including % spin lost or gained in mist conditions over dry conditions.

Dry Mist Club (rpm) (rpm) % Diff Comparison Sample #1 8732 3698 −57.6 Inventive Sample #1 8785 6236 −29.0 Inventive Sample #2 8650 7184 −17.0 Comparison Sample #2 8716 5654 −35.1 Comparison Sample #3 8634 4759 −44.9

Again, Inventive Sample #2 performed the best followed by Inventive Sample #1.

Thus it was discovered that the grooves in accordance with this invention provided excellent spin results, and particularly, less loss of spin under mist (wet) conditions. Dispersion results were also improved. This allows the golfer to be more consistent in his/her game (e.g., the golfer can feel more confident that the club will perform similarly under different conditions of play).

In a third test, club head performance was compared with respect to ball speed for a 30 yard test shot and the results are presented in the following table:

Dry Mist Club (mph) (mph) % Diff Comparison Sample #1 40.7 39.5 −2.9 Inventive Sample #1 42.5 41.7 −1.9 Inventive Sample #2 41.0 40.4 −1.5 Comparison Sample #2 41.6 40.9 −1.7 Comparison Sample #3 42.0 41.0 −2.5

In a fourth test, club heads performance was compared with respect to ball speed for a 60 yard test shot, and the results are presented in the following table:

Dry Mist Club (mph) (mph) % Diff Comparison Sample #1 60.7 58.6 −3.5 Inventive Sample #1 60.8 59.2 −2.6 Inventive Sample #2 61.8 60.7 −1.9 Comparison Sample #2 61.8 60.4 −2.3 Comparison Sample #3 62.2 60.7 −2.4

This data demonstrates that the ball speed does not substantially suffer (or is not substantially degraded) for the Inventive Sample grooves under wet conditions. While the inventive grooves show improved maintenance of spin rate under wet conditions, the inventive grooves also showed similar, if not somewhat improved ball speed performance as compared to the other grooves from a ball speed loss point of view (i.e., the inventive grooves lost less ball speed or substantially the same ball speed (wet v. dry) when compared to the other grooves). Thus, again, one using the club would see little change in ball speed performance (wet v. dry), and thus one would expect the ball to fly similar distances (wet v. dry).

In a fifth test, club head performance was compared with respect to launch angle for a 30 yard test shot, and the results are presented in the following table:

Club Dry (°) Mist (°) % Diff Comparison Sample #1 25.6 35.1 37.0 Inventive Sample #1 25.7 31.5 22.4 Inventive Sample #2 26.2 31.5 20.0 Comparison Sample #2 27.2 34.2 26.0 Comparison Sample #3 26.2 35.5 35.3

In a sixth test, club heads performance was compared with respect to launch angle for a 60 yard test shot, and the results are presented in the following table:

Club Dry (°) Mist (°) % Diff Comparison Sample #1 25.2 34.3 36.2 Inventive Sample #1 26.0 31.3 20.5 Inventive Sample #2 25.9 28.8 11.3 Comparison Sample #2 24.6 31.6 28.6 Comparison Sample #3 25.4 33.3 30.9

This data shows that the launch angle does not change as much for the Inventive Grooves (wet v. dry) as the other grooves. Again, this would make the club head having grooves according to the present invention perform more consistently under different play conditions (wet v. dry) than the clubs with the other grooves.

In a seventh test, club head performance was compared with respect to maximum height during flight for a 30 yard test shot, and the results are presented in the following table:

Dry Mist Club (yds.) (yds.) % Diff Comparison Sample #1 3.8 5.7 49.2 Inventive Sample #1 4.3 5.4 27.3 Inventive Sample #2 4.1 5.1 24.3 Comparison Sample #2 4.4 6.0 37.8 Comparison Sample #3 4.4 6.3 42.6

In an eighth test, club head performance was compared with respect to maximum height during flight for a 60 yard test shot, and the results are presented in the following table:

Dry Mist Club (yds.) (yds.) % Diff Comparison Sample #1 9.5 13.1 37.0 Inventive Sample #1 9.6 11.6 20.7 Inventive Sample #2 9.8 10.9 10.6 Comparison Sample #2 10.0 12.9 28.3 Comparison Sample #3 9.9 13.7 37.8

This data demonstrates that the ball's maximum launch height does not change as much for the Inventive grooves under different conditions of play (wet v. dry) as compared to the other grooves. One using the clubs with the Inventive grooves would see little change in maximum ball launch height under different play conditions (wet v. dry), and thus one would expect the ball to fly more similar distances under these different conditions (wet v. dry).

In a ninth test, club head performance was compared with respect to total carry distance for a 30 yard test shot, and the results are presented in the following table:

Dry Mist Club (yds.) (yds.) % Diff Comparison Sample #1 28.3 29.6 4.6 Inventive Sample #1 31.3 32.1 2.4 Inventive Sample #2 29.6 30.1 1.6 Comparison Sample #2 30.4 31.8 4.7 Comparison Sample #3 31.2 31.8 1.7

In a tenth test, club head performance was compared with respect to total carry distance for a 60 yard test shot, and the results are presented in the following table:

Dry Mist Club (yds.) (yds.) % Diff Comparison Sample #1 60.1 61.1 1.7 Inventive Sample #1 59.9 60.6 1.2 Inventive Sample #2 62.0 62.6 0.2 Comparison Sample #2 62.1 63.1 1.7 Comparison Sample #3 63.2 64.4 1.9

This data demonstrates that the ball carry distance does not substantially change (or is not substantially degraded) for the Inventive grooves under wet conditions. While the inventive grooves show improved maintenance of spin rate under wet conditions, the inventive grooves also showed similar, if not somewhat improved, wet. dry ball carry distance performance as compared to the other grooves (i.e., in wet conditions, the inventive grooves performed close to the same as the dry grooves, and the inventive grooves performed substantially the same, if not somewhat better than the other grooves). Thus, again, one using the club of the invention would see little change in ball carry performance (wet v. dry), and thus one would expect the ball to fly similar distances (wet v. dry).

In an eleventh test, club head performance was compared with respect to side-carry for a 30 yard test shot, and the results are presented in the following table:

Club Dry Mist % Diff Comparison Sample #1 0.0 −0.8 0.77 Inventive Sample #1 −0.4 −1.7 1.29 Inventive Sample #2 0.1 −0.4 0.50 Comparison Sample #2 0.2 −0.3 0.52 Comparison Sample #3 0.1 −0.6 0.72

In a twelfth test, club heads performance was compared with respect to side-carry for a 60 yard test shot, and the results are presented in the following table:

Club Dry Mist % Diff Comparison Sample #1 0.9 −0.7 1.55 Inventive Sample #1 1.5 0.8 0.69 Inventive Sample #2 −0.7 −1.0 0.32 Comparison Sample #2 0.9 0.3 0.65 Comparison Sample #3 0.1 −1.6 1.69

This data demonstrates that the Inventive grooves perform comparable to the other grooves from a side carry point of view (“side carry” refers to the amount the ball drifts off the initial center flight line, e.g., due to inducement of side spin on the ball). The wet v. dry data for the inventive grooves is similar to (or even somewhat improved for Inventive Sample 2) the wet v. dry performance data for the other clubs.

In view of the above data, a player using a club with the Inventive grooves could perform more consistently under wet or dry conditions (i.e., the stroke can be played substantially the same in wet or dry conditions and the ball could be expected to react similarly, wet v. dry). This gives the player less variables and more confidence when making the stroke. The data shows the Inventive grooves to be better at maintaining wet to dry performance then the Comparative grooves for spin performance (i.e., less reduction in spin wet v. dry), launch angle performance (i.e., less change in launch angle wet v. dry), and maximum ball height performance (i.e., closer to the same maximum height wet v. dry). The data also show that the Inventive grooves perform substantially the same as (and in some instances, somewhat improved to) the Comparative grooves for ball speed performance (i.e., reduction in spin wet v. dry), carry distance performance (i.e., change in carry distance wet v. dry), and side carry performance (i.e., stays closer to the launch direction wet v. dry).

While aspects of this invention have been described for use in conjunction with conforming grooves (conforming to the 2010-2011 USGA groove regulations), this is not a requirement. Rather, if desired, aspects of this invention may be applied to golf club heads with any desired types of conforming or non-conforming grooves.

CONCLUSION

While the invention has been described in detail in terms of specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and methods. Thus, the spirit and scope of the invention should be construed broadly as set forth in the appended claims. 

What is claimed is:
 1. A golf club head comprising a substantially flat striking face and a plurality of grooves formed therein, wherein at least one of said grooves comprises: side walls wherein each side wall slopes inwardly from the striking face toward a bottom of the groove at an angle of 25.5 to 28.5 degrees from an axis of symmetry extending perpendicular from the striking face; a depth extending perpendicular from the striking face to the bottom of the groove of 0.013 to 0.018 inch; and wherein spacing between adjacent groove edges is 0.085 to 0.098 inches.
 2. The golf club head of claim 1 wherein the angle is 26.5 to 27.5.
 3. The golf club head of claim 1 wherein the depth is 0.015 inches to 0.017 inches.
 4. The golf club head of claim 1 wherein the spacing is 0.090 to 0.095 inches.
 5. The golf club head of claim 1 wherein the area of each of said grooves divided by groove pitch is 0.0018 to 0.0030 in²/in.
 6. The golf club head of claim 1 wherein the area of each of said grooves divided by groove pitch is 0.0023 to 0.0030 in²/in.
 7. The golf club head of claim 1 wherein a groove area (A) is 0.00028 to 0.00036 in².
 8. The golf club head of claim 1 wherein the grooves comply with the USGA Rules of Golf dated 2011-2012.
 9. A golf club head comprising a substantially flat striking face and a plurality of grooves formed therein, wherein at least one of said grooves comprises: side walls wherein each side wall slopes inwardly from the striking face toward a bottom of the groove at an angle of 25.5 to 28.5 from an axis of symmetry extending perpendicular from the striking face; a depth extending perpendicular from the striking face to the bottom of the groove of 0.013 to 0.018 inch; and a width at the top of the groove of 0.025 to 0.030 inches.
 10. The golf club head of claim 9 wherein the angle is 26.5 to 27.5.
 11. The golf club head of claim 9 wherein the depth is 0.015 inches to 0.017 inches.
 12. The golf club head of claim 9 wherein the area of each of said grooves divided by groove pitch is 0.0018 to 0.0030 in²/in.
 13. The golf club head of claim 9 wherein the area of each of said grooves divided by groove pitch is 0.0023 to 0.0030 in²/in.
 14. The golf club of claim 9 wherein a groove area (A) is 0.00028 to 0.00036 in²
 15. The golf club head of claim 9 wherein the grooves comply with the USGA Rules of Golf dated 2011-2012.
 16. A golf club head comprising a substantially flat striking face and a plurality of grooves formed therein, wherein at least one of said grooves comprises: side walls wherein each side wall slopes inwardly from the striking face toward a bottom of the groove at an angle of 25.5 to 28.5 from an axis of symmetry extending perpendicular from the striking face; and a width at the top of the groove of 0.025 to 0.030 inches; wherein spacing between adjacent grooves is 0.085 to 0.098 inches.
 17. The golf club head of claim 16 wherein the angle is 26.5 to 27.5.
 18. The golf club head of claim 16 wherein the spacing is 0.090 to 0.095 inches.
 19. The golf club head of claim 16 wherein the area of each of said grooves divided by groove pitch is 0.0018 to 0.0030 in²/in.
 20. The golf club head of claim 16 wherein the area of each of said grooves divided by groove pitch is 0.0023 to 0.0030 in²/in.
 21. The golf club of claim 16 wherein a groove area (A) is 0.00028 to 0.00036 in²
 22. The golf club head of claim 16 wherein the grooves comply with the USGA Rules of Golf dated 2011-2012.
 23. A golf club head comprising a substantially flat striking face and a plurality of grooves formed therein, wherein at least one of said grooves comprises: side walls wherein each side wall slopes inwardly from the striking face toward a bottom of the groove at an angle of 25.5 to 28.5 degrees from an axis of symmetry extending perpendicular from the striking face; a depth extending perpendicular from the striking face to the bottom of the groove of 0.013 to 0.018 inch; a groove width extending across the top of the groove of 0.025 to 0.030 inch; a groove area is 0.00028 to 0.00036 in²; wherein the area of each of said grooves divided by groove pitch is 0.0018 to 0.0030 in²/in; wherein spacing (S) between adjacent grooves is 0.085 to 0.095 inches; and the loft angle of the club head is 44° to 70°. 